The present invention relates to techniques for visualizing multi-scale data on a display.
Determining properties of subsurface earth formation is a critical element in maximizing the profitability of oil and gas exploration and production. In order to improve oil, gas, and water exploration, drilling, and production operations, it is necessary to gather as much information as possible on the properties of the underground earth formations as well as the environment in which drilling takes place. Thus, well logging typically produce a large amount of information that needs to be analyzed to provide insights into the formation properties. The data to be analyzed are typically derived from logging operations using different instruments to probe various geophysical properties. Each of these instrument may generate an enormous amount of data, rendering the analysis difficult. In addition, it is often necessary to compare and contrast data from different measurements to gain insights into the formation properties.
For example, neutron tools are often used to provide information on formation porosity because formation liquids in pores interact with neutrons. However, because both water and hydrocarbons produce signals in neutron measurements, neutron logging data by themselves cannot reveal which pores contain water and which contain hydrocarbons. On the other hand, resistivity tools can easily differentiate whether a formation liquid is water or hydrocarbons, due to the high contrast in resistivity/conductivity in these two types of fluids. A combined use of these two measurements can provide information as to which formation pores contain hydrocarbons. In order to derive useful information from various formation logging data, it is a common practice to present each measurement data set in a strip chart graph (“track”) and align various graphs side by side for analysis.
For example, FIG. 1 shows a typical prior art methods of presenting a a plurality of logging data as side-by-side tracks for analysis. The presentation shown in FIG. 1 is a standard format prescribed in, for example, Standard Practice 31A, published by the American Petroleum Institute, Washington, D.C. In this example, tracks 50, 54, 56 each include a header 57 which indicates the data type(s) for which a data curve or curves 51, 53, 55, 59 are presented in each track. Well log data are typically recorded with reference to the depth of well. A depth track 52, which shows the measured depth (MD, the depth from the top of the well) of the data, is typically included in the graph as shown in FIG. 1 to provide a representation of the well.
A presentation such as shown in FIG. 1 may include in the various curves 51, 53, 55, 59 “raw”data, such as detected voltages, detector counts, etc. actually recorded by well log instrument, or more commonly, a parameter of interest that is derived from the raw data, such as gamma density, neutron porosity, resistivity, acoustic travel time, etc.
The data tracks presented in a conventional graph (e.g., curves 51, 53, 55, 59 in tracks 50, 54, 56 of FIG. 1) do not lend themselves to intuitive interpretation by a user. In addition, linearization of a well may obscure valuable information that is dependent on the geometry of the well or the size of the borehole. In this conventional representation, the measurement data are dissociated from the physical structure of the wellbore. A more preferred method would be to display these data alongside the three-dimensional (3D) borehole trajectory. A borehole is typically of no more than a foot in diameter, but up to several miles long winding around in the subsurface formation. The thin and long 3D structure of the wellbore makes it difficult for a user to see the overall picture of the wellbore and at the same time to be able to see enough details in a selected section.
Therefore, it is desirable to have methods and systems that permit a user to manipulate a big 3D object easily and at the same time to be able to analyze a data associated with a particular section in details.